Fiberglass Cloth Help

Discussion in 'Materials' started by Toms17, Dec 12, 2019.

  1. Toms17
    Joined: Dec 2019
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    Location: Spokane WA

    Toms17 New Member

    I am planning a large wet layup over marine grade plywood. I bought 6oz S glass 8H Satin Weave 70x73 matt without thinking about how tight of a weave that was. I am concerned about trapping bubbles in the layup process.

    I understand I need a low viscosity resin with such a tight weave and the only resin with an acceptable heat resistance is a 25 minute pot life, so not a large amount of working time. I have layups that are up to 45 square feet at a time, so moderately large. I do have the aluminum rollers to help remove air bubbles.

    Does anyone have advice on if I should proceed using this tight weave matt with the materials I have described? Or should I bite the bullet and just get an open weave 18x18 weave matt?

    Any help would be outstanding
  2. Mr Efficiency
    Joined: Oct 2010
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    Mr Efficiency Senior Member

    "acceptable heat resistance" ? What are you speaking of ?
  3. Toms17
    Joined: Dec 2019
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    Location: Spokane WA

    Toms17 New Member

    Most resins I have found have low TG ultimate temperatures. I am looking for something over 170degrees F, and only Fibreglasts System 1000 resins meet that and the viscosity requirement. That system just doesnt have a long open time
  4. Yellowjacket
    Joined: May 2009
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    Yellowjacket Senior Member

    First, get some help. You need at least three people to work this kind of a layup. You can work in small batches and work from one end toward the other. That way if part of it starts to jell it's already well laid down and isn't going to get messed up. Also, small batches don't kick off as quickly because they don't get as hot. If you had two people brushing and working out the layup and one person mixing you could probably do it all before the first part gelled. If you were to try to do this with just one person it could get ugly. I did the bottom of a race boat that was about 45 sq ft and it was difficult as I was using a vinyl overlay to get a smooth finish in one shot, and without help it would have been a disaster. Three is safety in numbers.
    BlueBell likes this.
  5. Toms17
    Joined: Dec 2019
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    Location: Spokane WA

    Toms17 New Member

    Thanks for the advice Yellowjacket. I definitely plan to have help.
    My main concern is using such a tightly woven cloth and getting the air bubbles out. I've only ever worked with an 18x18 open weave before that released air quickly. It's more of an industrial cloth and after reading more about it (after purchasing) I read it wasn't recommended for contact layups like over plywood because of trapped air.

  6. KD8NPB
    Joined: Mar 2018
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    Location: South Carolina

    KD8NPB Senior Member

    Why do you need such a high HDT?

    Vipel, Hetron, and Derakane are sold unpromoted/unaccelerated so you can promote/accelerate to whatever gel time you need with whatever initiator you're using.

    For most noobs, I'd say you just need to buy some standard 40 minute 100% VE such as Ashland AME6441 or AOC H100. If the glass is properly made with the correct sizing, wetout will be a non issue. If you're hyper concerned about small air bubbles in the laminate, you should vacuum infuse.

    Just an FYI, with open mold hand rolled laminates, air bubbles up to about 1/16" to 1/32" in diameter are "acceptable" in, they are unlikely to cause a severe problem, and they're almost unavoidable in a production environment. If they're a concern, then you should hand-lay a resin rich layer such as a surface veiling against the part first.
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